A study by David Cummings et. al. published in Diabetalogia investigated the mounting evidence indicates that Roux-en-Y gastric bypass (RYGB) ameliorates type 2 diabetes.
32 adults were divided into 2 groups. In the ILMI [intensive lifestyle and medical intervention] group, the individuals performed ≥45 min of aerobic exercise 5 days per week, a dietitian-directed weight- and glucose-lowering diet, and optimal diabetes medical treatment for 1 year. In the RYGB group, the individuals received Roux-en-Y gastric bypass (RYGB).
Diabetes remission at 1 year was 60.0% with RYGB vs 5.9% with ILMI (p = 0.002). Compared with the most rigorous ILMI yet tested against surgery in a randomised trial, RYGB yielded greater type 2 diabetes remission in mild-to-moderately obese patients recruited from a well-informed, population-based sample.
http://link.springer.com/article/10.1007%2Fs00125-016-3903-x
I am almost 3 years post-op RNY surgery. I had Type 2 diabetes and took 2 types of medication prior to surgery. When I left the hospital 2 days after surgery, my diabetes went into remission and I went off my meds. It has stayed in remission ever since. Many individuals on this website report similar results. But a few don't. From prior posts, one of the variables for success appears to be the length of time the individual had diabetes prior to surgery. So one of the interesting points of this study is:
The groups were equivalent regarding all baseline characteristics, except that the RYGB cohort had a longer diabetes duration (11.4 ± 4.8 vs 6.8 ± 5.2 years, p = 0.009).